Hi everyone!

I need help with my 1994 Honda accord( it's a stick shift), the engine has rough idle and it sounds loud! I've already replaced the spark plugs, spark plug wires and distributor. In addition, the engine seems to release smog smell from engine bay.

Please see photo of the Exhaust Manifold below, it appears cracked. Is this the reason why the engine bay smells a lot like smog??

The rough idle happens every time I start to turn the steering wheel or when the AC is turned on(please see video). Is it normal?

Finally, the engine sounds like a diesel engine(please see video). Not sure what could be causing this, can someone please help?

Thank you!